If you have not yet seen the film, I advise you to skip this post. Since I had just reread the book, I was more conscious of the differences between the book and film than I typically have been when seeing the movies.
These are some of the things I noted:
- I liked the movie's scene in which Hermione erases her parents' memories--this was only described after the fact in the book.
- I liked the book's scene in which Harry says goodbye to the Dursleys, and Dudley shows a glimpse of humanity. This was not in the film.
- The story behind Tonks and Lupin's relationship is very sketchy in the film, but much more fully fleshed out in the book. Lupin has a crisis of confidence because he is a werewolf, and he actually has a falling-out with Harry over this issue. I was disappointed they didn't give as much background here.
- Most of the preparations for Bill and Fleur's wedding are taken out, and in fact this movie is the first time Bill shows up on film (which is odd in itself). In the book, they give Harry polyjuice potion so he can be disguised as Ron's cousin at the wedding (to protect his safety). In the film, he's there as himself, which doesn't make much sense.
The wedding is tremendously shortened and Victor Krum is not there and therefore does not get upset at the symbol on Luna's dad's cloak. In addition, the scene with Rufus Scrimgeour (played by the great Bill Nighy) was much less tense and strained than it is in the book. Scrimgeour's role is much more minor. I realize they could not include everything in the novel, but it seems that the first part of the book was extremely short in the movie.
- Harry, Ron, and Hermione rarely use the invisibility cloak in the movie, unlike in the book. I can understand why they did that (it's much more effective to be able to actually see the characters), but as a result it seems that they are less careful in the film. They also spend hardly any time plotting their break-in to the ministry, whereas in the book they plot for days or weeks about how to do this.
- Harry and Hermione have a very sweet little dance in the film, which does not exist in the book. It's purely platonic and friendly, although it struck me that if someone had not read the book, he or she might assume that a love triangle existed where it did not.
- Many of the important facts about Kreacher, Sirius Black, horcruxes, Xenophilius Lovegood, Albus Dumbledore, and Lupin and Tonks are left out of the film. Movie goers who have not read the book are far less likely to appreciate the nuances of the story. When I was reading the final book, I was marveling at JK Rowling's ingenuity and creativity. She wove such a tangled web in the plot, and it's not as deeply explored on film.
- When Harry and Hermione return to Godric's Hollow, they see Harry's parents' house as kind of a memorial to them. They realize that it's enchanted, and only witches and wizards can see it.
- When Ron leaves Harry and Hermione in a snit, in the book he goes to stay with Bill and Fleur and he learns all about the radio show, Potterwatch. He also learns that the death eaters are able to track people when they say "Voldemort" out loud. None of this was in the movie.
- One of the most significant differences is that in the book, Harry is quite disenchanted with Dumbledore. He learns from reading Rita Skeeter's book that Dumbledore dabbled in the dark arts and was not as noble as Harry always thought. This is barely touched on in the film, but it might come up in Part 2.
- Peter Pettigrew does not die in the film...I'm not sure why they made that change.
- I liked the animated tale of the three brothers in the movie. It resulted in a much more colorful and vivid portrayal of the story.
- One of the most unbelievable parts of the movie was when Hermione is in the forest and sees the snatchers. Although Hermione has raised a protective enchantment, the snatchers can smell her there. Later she tells Harry in horror that she thinks they could smell her perfume. I found the idea of Hermione wearing perfume in the forest to be inconceivable, especially since they could be on the run at any moment and having to evade capture. This was a ridiculous Hollywood addition.